Another potentially deadly problem has surfaced with Takata air bags, this one forcing BMW to recall over 4,000 SUVs in the U.S. and Canada.

The new problem was traced to improper welds, and it's separate from the trouble that has caused the largest automotive recall in U.S. history.

The latest recall, unveiled Friday in documents posted by the National Highway Traffic Safety Administration, affects certain BMW X3 and X4 SUVs from the 2015 model year, and X5s from 2014 and 2015. The driver's front air bag inflator can separate from a plate, shooting out metal and other debris. "This may result in injury or death to vehicle occupants," BMW said in the documents.

No injuries have been reported, and NHTSA says the problem inflators from this manufacturing lot were not installed in any other vehicles made by BMW or other automakers. The agency says the inflators will be tested as a precaution to make sure there are no other problems. BMW says the inflators were not part of any earlier Takata recalls.

"Indications thus far are that this issue is isolated to approximately 4,000 parts, and we are unaware of any injuries as a result of the issue," Takata said in a statement, adding that it continues to investigate and work with BMW to address concerns.

It's a new problem for Takata in addition to the one that brought the recall of 69 million vehicles in the U.S. and about 100 million worldwide. In those vehicles, the ammonium nitrate used by Takata to inflate air bags can deteriorate when exposed to high heat and humidity.

That can cause it to burn faster than designed, blowing apart a metal inflator canister and sending shrapnel into drivers and passengers. As many as 15 people, including 10 in the U.S., have been killed by exploding Takata inflators, and more than 100 have been hurt.

According to the documents, Takata traced the problem to incorrect welds at a factory in Mexico. The defect was discovered after BMW was told of a July 22 crash in Georgia involving a 2014 X5 in which shrapnel from the air bag caused "unusual damage to the vehicle interior."

Dealers will replace the driver's air bag at no cost, but parts aren't available yet. Until replacement parts are ready, BMW says its dealers will provide loaner cars to people who request them, provided they are available. BMW plans to start notifying owners on Nov. 11. (ags)